35 slide overview of Ventilatory Failure

1. RT 7
M. Welch, RRT, RCP
Professor
ELAC / SMC RT Program
Spring 2022

2. Respiratory failure is syndrome rather
than single disease process. RECALL:
 Oxygenation failure = Type I
◦ PaO2 < 60 mm Hg at FiO2 > .50
 Ventilatory failure = Type II
◦ PaCO2 > 45 mm Hg
 Classification relates to the absence
or presence of hypercapnia
respectively.

3.  Oxygenation Failure = Type I
◦ Characterized by an arterial
oxygen tension (Pa O2) lower than
60 mm Hg w/ normal or low
carbon dioxide tension (Pa CO2).
◦ Most common form of respiratory
failure
◦ Can be associated with virtually all acute
diseases of the lung which generally involve
fluid filling or collapse of alveolar units

4.  Ventilatory failure = Type II
◦Characterized by a PaCO2 higher
than 45 mm Hg.
◦ Hypoxemia common in patients w/
hypercapnic respiratory failure who
are breathing room air.
◦ pH depends on the level of
bicarbonate, which is dependent on
the duration of hypercapnia.

6.  Acute: abnormal elevation of the
PaCO2 without renal compensation
 Chronic: abnormal elevation of the
PaCO2 with renal compensation
(abnormal Base Excess [BE] with the
pH in normal range)
 Mixed: a combination of acute and
chronic (abnormal BE but the pH is not
in the normal range)

7. Acute RF
Chronic RF
 Develops over
minutes to hours
 ↓ pH quickly to <7.2
 Examples:
Pneumonia,
 ARDS
 P/O Pt’s
 Develops over
days
 ↑ in HCO3
 ↓ pH slightly
 Polycythemia, Cor
pulmonale
 Example: COPD

8.  Dysfunction of Central Nervous
System (CNS)
◦(Depression of respiratory centers)
Drug Overdose
Head Trauma
Infection
Hemorrhage
Sleep Apnea

9. ◦Neuromuscular disease
Cerebral disease
Spinal cord trauma / injury
abnormalities
Muscular diseases
 Myasthenia Gravis
 Guillian-Barre syndrome
 Poliomyelitis
 Amyotropic Lateral Sclerosis / ALS
 AKA?


10. Musculoskeletal Dysfunction
◦Chest Trauma
◦Thoracic cage abnormalities
 Kyphoscoliosis
◦Upper and lower airway
obstruction
◦Malnutrition & electrolyte
disturbances

11. Pulmonary Dysfunction
◦Emphysema
◦Chronic Bronchitis
◦Asthma
◦Cystic Fibrosis
◦Restrictive lung diseases

12. e.g. Drug overdose
Change in respiration
Acidosis
Elevated PaCO2

13. Pathophysiology:
◦Increased PaCO2
◦decreased pH
◦Acidosis
◦Somnolence
◦Coma

15.  Respiratory failure may be associated
with a variety of clinical
manifestations.
◦ However, most are nonspecific, & very significant
respiratory failure may be present without
dramatic signs or symptoms.
 This emphasizes the importance of
measuring arterial blood gases in all
patients who are seriously ill or in whom
respiratory failure is suspected.

16.  Complete blood count (CBC) may
indicate anemia
◦ can also contribute to tissue hypoxia
◦ polycythemia may indicate chronic hypoxemic
respiratory failure.
 A chemistry panel may be helpful in the
evaluation and management of a patient in
respiratory failure.
◦ Abnormalities in electrolytes such as potassium,
magnesium, and phosphate may aggravate
respiratory failure and other organ function.

17.  Chest radiography is essential in
evaluation of respiratory failure because
it frequently reveals cause.
◦ Distinguishing between cardiogenic & noncardiogenic
pulmonary edema often difficult.
 Increased heart size / vascular redistribution /
peribronchial cuffing
 pleural effusions / septal lines / perihilar bat-wing
distribution of infiltrates suggest hydrostatic edema
◦ the lack of these findings suggests acute respiratory
distress syndrome (ARDS).

18.  Patients with acute respiratory
failure generally are unable to
perform PFTs;
◦These tests most useful in the
evaluation of chronic respiratory
failure.

19. Nonspecific:
◦Headache
◦Diminished alertness
◦Warm & flushed skin
◦Bounding peripheral pulses
◦Hypothermia and altered mental
status = drug OD

20. Nonspecific:
◦Tachycardia & hypertension
◦Respiratory alternans or
abdominal paradox
 = diaphragmatic fatigue
◦Hypoxemia is often seen in
conjunction with ventilatory
failure

21. Laboratory abnormalities
(ABG)
◦High PaCO2
◦Acidemia if Acute
◦Elevated total CO2 on
electrolyte panel

22. •Specific treatment of oxygenation &
/or ventilatory failure C/B Drug
Overdose (Narcotic / Barbiturate / alcohol )
 Identify type of drug, amount ingested and time
since ingestion.
 Diagnose and treat trauma.
 Prevent and/or treat aspiration; look for right lower
lobe crackles
 intubate if suspected or confirmed
 CMV to reestablish and maintain normal PaCO2
 100% oxygen initially then reduce FIO2 to maintain
clinical oxygenation

23. •Specific Treatment of oxygenation
& /or ventilatory failure C/B Drug
Overdose (Narcotic / Barbiturate / alcohol)
 Prevent drug absorption:
 Stomach lavage
◦ watch for aspiration
 Induce vomiting
 Charcoal
 Dialysis
 Administer antidote, i.e.: Narcan, etc.
 Psychiatric consult

24. ◦IF severe/acute most likely
invasive MV
◦HOWEVER:
◦IF patient awake and able to
cooperate with care and is
suspected COPD or CHF
Exacerbation: NIV is now the
preferred approach
◦IF NIV fails, then MV is instituted

25.  PRIOR to NIV, often the following are considered:
◦ HFNC What are the possible beneficial effects?
 High-flow system to deliver known FIO2
 Provide small amount of “CPAP” 2-5 or 6 cmH2O ?
1 cmH2O per every 10 Lpm?
 “wash out” anatomical deadspace of oralpharynx
 Reduce Insp. WOB by small, but statistically significant
amount
 Potential benefits of heated humidification on mucus? Not
well studied, but appears to have some “clinical effect”?
◦ Very frequent/intensive bronchodilators? (COPD Pt)
◦ MediNeb therapy? (COPD Pt)
◦ CPAP? (Defined as NIV by many)
 What is the PRIMARY difference between CPAP and BiPaP?

26. Mechanical ventilation
 First: Rapid Sequence Intubation f/b
◦ VT 5–8 ml/kg IBW
◦ Keep Pplateau < 35 cm H2O
◦ Respiratory rate according to age and
metabolic rate
◦ FiO2 adjusted with pulse oximetry
◦ Treat cause of ventilatory failure
◦ Wean from CMV as soon as possible
(ASAP)

27. Weaning criteria
◦ Etiology of ventilatory failure resolved
◦ Patient’s condition stable and improving
◦ Vital capacity (VC) > 10–15 mL/kg
◦ Resting minute volume < 10 L/min
◦ MIP > -20 cm H2O
◦ Adequate oxygenation on FiO2 < .50
◦ Spontaneous respiratory rate < 35
breaths/min
◦ Spontaneous tidal volume > 325 mL

28.  Weaning Methods:
◦SIMV
 Decrease number of mechanical breaths until
support is no longer necessary
◦Pressure Support
 Set to acceptable tidal volume and rate without use
of accessory muscles and wean thereafter
◦ T-Piece
 AKA: SBT (Spontaneous Breathing Trial)
 Temporary discontinuation of mechanical ventilation
 “Blow-by” of appropriate FiO2

29.  Complications of acute respiratory
failure may be:
◦ Pulmonary
◦ Cardiovascular
◦ Gastrointestinal (GI)
 Stress ulceration common
◦ Infectious
◦ Renal
 Acute renal failure & electrolyte abnormalities
◦ Nutritional
 Malnutrition & effect on respiratory performance

30.  Common pulmonary complications include:
◦ Pulmonary embolism
◦ Oxygen toxicity
◦ CO2 narcosis
◦ Barotrauma
◦ Pulmonary fibrosis
◦ Complications secondary to the use of CMV devices
 Patients also prone to develop nosocomial
pneumonia (VAP)
 Pulmonary fibrosis may follow acute lung
injury associated with ARDS.

31.  Common cardiovascular complications
include:
◦ Hypotension
◦ Reduced cardiac output
◦ Arrhythmia
◦ Pericarditis
◦ Acute myocardial infarction (AMI)
 These may be related to the underlying
disease process, mechanical ventilation, or
the use of pulmonary artery catheters

32.  Frequent infectious complications
or nosocomial infections such as:
◦ Pneumonia
◦ Urinary tract infections (UTI’s)
◦ Catheter-related sepsis
 These usually occur with the use of
mechanical devices.
 Incidence of nosocomial pneumonia is
high & associated with significant
mortality.

33.  Mortality associated with respiratory
failure varies according to the etiology.
◦ For ARDS, mortality is approximately 40-45%;
 This figure has not changed significantly over the
years.
◦ Younger patients (< 60 y) have better survival
rates than older patients.
◦ Approximately two thirds of patients who
survive an episode of ARDS manifest some
impairment of pulmonary function 1 or more
years after recovery.

34. ◦ Significant mortality also occurs in patients
admitted with hypercapnic respiratory failure.
 Often because these patients have a chronic
respiratory disorder & other comorbidities such as
cardiopulmonary, renal, hepatic, or neurologic
disease.
 These patients also may have poor nutritional status.
◦ For patients with COPD and acute respiratory
failure, the overall mortality has declined from
approximately 26% to 10%.
◦ Acute exacerbation of COPD carries a mortality
of approximately 30%.

35. “A surplus of effort
can overcome a
deficit of
confidence."
Sonia Sotomayor, 2013